Method of manufacturing a semiconductor device

ABSTRACT

A semiconductor device including an active pattern on a substrate and extending lengthwise in a first direction parallel to an upper surface of the substrate; a gate structure on the active pattern, the gate structure extending in a second direction parallel to the upper surface of the substrate and crossing the first direction; channels spaced apart from each other along a third direction perpendicular to the upper surface of the substrate, each of the channels extending through the gate structure along the first direction; a source/drain layer on a portion of the active pattern adjacent to the gate structure in the first direction, the source/drain layer contacting the channels; inner spacers between the gate structure and the source/drain layer, the inner spacers contacting the source/drain layer; and channel connection portions between each of the inner spacers and the gate structure, the channel connection portions connecting the channels with each other.

CROSS-REFERENCE TO RELATED APPLICATIONS

This is a continuation application based on pending application Ser. No.16/943,103, filed Jul. 30, 2020, the entire contents of which is herebyincorporated by reference.

This application claims priority under 35 U.S.C. § 119 to Korean PatentApplication No. 10-2020-0004680, filed on Jan. 14, 2020, in the KoreanIntellectual Property Office, and entitled: “Semiconductor Devices,”which is incorporated by reference herein in its entirety.

BACKGROUND 1. Field

Embodiments relate to a semiconductor device.

2. Description of the Related Art

When a multi-bridge channel field effect transistor (MBCFET) including aplurality of channels spaced apart from each other along a verticaldirection (each of which extending through a gate structure in ahorizontal direction) is formed, a source/drain layer commonlycontacting the channels may be formed, and an inner spacer may be formedbetween the gate structure and the source/drain layer to electricallyinsulate the gate structure from the source/drain layer.

SUMMARY

The embodiments may be realized by providing a semiconductor deviceincluding an active pattern on a substrate, the active pattern extendinglengthwise in a first direction parallel to an upper surface of thesubstrate; a gate structure on the active pattern, the gate structureextending lengthwise in a second direction parallel to the upper surfaceof the substrate and crossing the first direction; channels spaced apartfrom each other along a third direction perpendicular to the uppersurface of the substrate, each of the channels extending lengthwisethrough the gate structure along the first direction; a source/drainlayer on a portion of the active pattern adjacent to the gate structurein the first direction, the source/drain layer contacting the channels;inner spacers between the gate structure and the source/drain layer, theinner spacers contacting the source/drain layer; and channel connectionportions between each of the inner spacers and the gate structure, thechannel connection portions connecting the channels with each other.

The embodiments may be realized by providing a semiconductor deviceincluding an active pattern on a substrate, the active pattern extendinglengthwise in a first direction parallel to an upper surface of thesubstrate; a gate structure on the active pattern, the gate structureextending lengthwise in a second direction parallel to the upper surfaceof the substrate and crossing the first direction; channels spaced apartfrom each other along a third direction perpendicular to the uppersurface of the substrate, each of the channels extending lengthwisethrough the gate structure along the first direction; a source/drainlayer on a portion of the active pattern portion adjacent to the gatestructure in the first direction, the source/drain layer contacting thechannels; and a channel connection portion and an inner spacersequentially stacked along the first direction between the gatestructure and the source/drain layer, the channel connection portionincluding a semiconductor material and the inner spacer includingsilicon nitride, wherein the gate structure includes an interfacepattern, a gate insulating pattern and a gate electrode sequentiallystacked along the first direction from the channel connection portion,the interface pattern including silicon oxide, the gate insulatingpattern including a metal oxide, and the gate electrode including ametal.

The embodiments may be realized by providing a semiconductor deviceincluding an active pattern on a substrate, the active pattern extendinglengthwise in a first direction parallel to an upper surface of thesubstrate; channels on the active pattern, the channels being spacedapart from each other along a third direction perpendicular to the uppersurface of the substrate; a gate structure extending lengthwise on theactive pattern in a second direction parallel to the upper surface ofthe substrate and crossing the first direction, the gate structure atleast partially covering each of the channels; source/drain layers atrespective opposite sides of the gate structure in the first direction,each of the source/drain layers contacting the channels; inner spacersbetween the active pattern and a lowermost one of the channels andbetween the channels, respectively, the inner spacers contacting thesource/drain layers; gate spacers covering respective opposite sidewallsof a portion of the gate structure on an uppermost one of the channels;and channel connection portions between the gate structure and acorresponding one of the inner spacers, the channel connection portionsconnecting the active pattern and the lowermost one of the channels, andconnecting the channels with each other, and the channel connectionportions covering an inner sidewall, an upper surface, and a lowersurface of a corresponding one of the inner spacers, wherein the gatestructure includes an interface pattern, a gate insulating pattern, agate electrode sequentially stacked from an surface of each of thechannels, an upper surface of the active pattern and an inner sidewallof the channel connection portion, the interface pattern including asilicon oxide, the gate insulating pattern including a metal oxide, andthe gate electrode including a metal.

BRIEF DESCRIPTION OF THE DRAWINGS

Features will be apparent to those of skill in the art by describing indetail exemplary embodiments with reference to the attached drawings inwhich:

FIGS. 1 to 4 are a plan view and cross-sectional views illustrating asemiconductor device in accordance with example embodiments.

FIGS. 5 to 24 are plan views and cross-sectional views of stages in amethod of manufacturing a semiconductor device in accordance withexample embodiments.

FIGS. 25 to 27 are cross-sectional views of stages in a method ofmanufacturing a semiconductor device in accordance with exampleembodiments.

FIGS. 28 and 29 are cross-sectional views illustrating semiconductordevices in accordance with example embodiments.

FIGS. 30 and 31 are cross-sectional views illustrating semiconductordevices in accordance with example embodiments.

DETAILED DESCRIPTION

Hereinafter, two directions substantially parallel to an upper surfaceof a substrate and crossing each other may be referred to as first andsecond directions, respectively, and a direction substantiallyperpendicular to the upper surface of the substrate may be referred toas a third direction. In example embodiments, the first and seconddirections may be substantially perpendicular to each other.

FIGS. 1 to 4 are a plan view and cross-sectional views illustrating asemiconductor device in accordance with example embodiments. FIG. 1 isthe plan view, and FIG. 2 is a cross-sectional view taken along a lineA-A′ in FIG. 1 . FIG. 3 is a cross-sectional view taken along a lineB-B′ in FIG. 1 , and FIG. 4 is an enlarged cross-sectional view of anarea X of FIG. 3 .

Referring to FIGS. 1 to 4 , the semiconductor device may include anactive pattern 105, a gate structure 300, a semiconductor pattern 126, achannel connection portion 127, and a source/drain layer 230 on asubstrate 100. The semiconductor device may further include a gatespacer 185, an inner spacer 220, an isolation pattern 130, and aninsulation layer 240.

The substrate 100 may include a semiconductor material such as silicon,germanium, or silicon-germanium, or a group III-V compound such asgallium arsenide (GaAs), aluminum gallium arsenide (AlGaAs), indiumarsenide (InAs), indium gallium arsenide (InGaAs), or the like.

The active pattern 105 may protrude from the substrate 100 in the thirddirection, and may extend (e.g., lengthwise) in the first direction. Inan implementation, as illustrated in the drawings, the device mayinclude two active patterns 105. In an implementation, more than twoactive patterns 105 may be spaced apart from each other in the seconddirection. The active pattern 105 may be formed by partially removing anupper portion of the substrate 100, and may include a materialsubstantially the same as that of the substrate 100.

A sidewall of the active pattern 105 facing in the second direction maybe covered by the isolation pattern 130. The isolation pattern 130 mayinclude, e.g., an oxide such as silicon oxide.

In an implementation, a plurality of semiconductor patterns 126 may beformed at a plurality of levels, respectively, to be spaced apart fromeach other in the third direction from an upper surface of the activepattern 105. In an implementation, as illustrated in the drawings, thesemiconductor patterns 126 may be at three levels, respectively.

In an implementation, as illustrated in the drawings, only twosemiconductor patterns 126 spaced apart from each other in the firstdirection may be at each level on the active pattern 105 and extendinglengthwise in the first direction. In an implementation, more than twosemiconductor patterns 126 may be formed to be spaced apart from eachother in the first direction at each level on the active pattern 105.

In an implementation, the semiconductor patterns 126 may include a firstsemiconductor pattern 126 a at an uppermost level (e.g., distal to thesubstrate 100 in the third direction), a third semiconductor pattern 126c at a lowermost level (e.g., proximate to the substrate 100 in thethird direction), and a second semiconductor pattern 126 b therebetween.

In an implementation, the semiconductor pattern 126 may be nanosheets ornanowires including a semiconductor material such as silicon, germanium,or the like. In an implementation, the semiconductor pattern 126 mayserve as a channel of a transistor, which may be referred to as thechannel.

The channel connection portion 127 may be between the first to thirdsemiconductor patterns 126 a, 126 b, and 126 c and between the activepattern 105 and the third semiconductor pattern 126 c so that the firstto third semiconductor patterns 126 a, 126 b, and 126 c and the activepattern 105 may be connected with each other in the third direction.

The channel connection portion 127 may include substantially the samematerial as the first to third semiconductor patterns 126 a, 126 b, and126 c, e.g., single crystal silicon.

In an implementation, a cross-section in the first direction of thechannel connection portion 127 may have a shape of a C or a reversed C.In an implementation, a cross-section in the first direction of thechannel connection portion 127 may have a shape of a ring in which aportion is cut in the first direction.

The gate structure 300 may be formed on the substrate 100, and maysurround a central portion of the semiconductor pattern 126 in the firstdirection. In an implementation, as illustrated in the drawings, thegate structure 300 may be formed on two active patterns 105 to cover therespective semiconductor patterns 126 thereon. In an implementation, thegate structure 300 may extend (e.g., lengthwise) in the second directionon the substrate 100 on which the isolation pattern 130 is formed, andmay be formed on more than two active patterns 105 spaced apart fromeach other in the second direction to cover the respective semiconductorpatterns 126 thereon, or may be formed only on one active pattern 105 tocover the semiconductor patterns 126 thereon.

In an implementation, as illustrated in the drawings, the substrate 100may have two gate structures 300 thereon. In an implementation, morethan two gate structures 300 may be formed to be spaced apart from eachother in the first direction on the substrate 100.

The gate structure 300 may include an interface pattern 260, a gateinsulating pattern 270, a work function control pattern 280, and a gateelectrode 290 sequentially stacked from a surface of the semiconductorpattern 126, an inner wall of the channel connection portion 127, and/orthe upper surface of the active pattern 105.

The interface pattern 260 may be on the upper surface of the activepattern 105, upper and lower surfaces of the semiconductor pattern 126,and the inner wall of the channel connection portion 127. The gateinsulating pattern 270 may be formed on the interface pattern 260. Thework function control pattern 280 may be formed on the gate insulatingpattern 270. The gate electrode 290 may fill a space between the activepattern 105 and the third semiconductor pattern 126 c, a space betweenthe second and third semiconductor patterns 126 b and 126 c, and a spacebetween the first and second semiconductor patterns 126 a and 126 b.

In an implementation, the interface pattern 260 may cover an entiresurface of the gate insulating pattern 270, and upper and lower surfacesof the semiconductor pattern 126 and the inner wall of the channelconnection portion 127 may be spaced apart from the gate insulatingpattern 270 so as to not contact the gate insulating pattern 270.

The interface pattern 260 may include, e.g., an oxide such as siliconoxide. The gate insulating pattern 270 may include, e.g., a metal oxidehaving a high permittivity such as hafnium oxide, tantalum oxide,zirconium oxide, or the like. The work function control pattern 280 mayinclude, e.g., titanium nitride, tantalum nitride, tungsten nitride,aluminum oxide, or the like. The gate electrode 290 may include, e.g., ametal such as titanium and aluminum, a metal alloy, or a nitride orcarbide of the metal.

The gate structure 300 may be electrically insulated from thesource/drain layer 230 by the gate spacer 185, the inner spacer 220, andthe channel connection portion 127.

In an implementation, the channel connection portion 127 may have aconvex shape that is closed toward a center of the gate structure 300along the first direction.

The gate spacer 185 may cover opposite sidewalls of the gate structure300 in the first direction, and may include, e.g., a nitride such assilicon oxynitride, silicon oxynitride, or the like.

The inner spacer 220 may be formed on a sidewall of the channelconnection portion 127 between the semiconductor patterns 126 spacedapart from each other in the third direction, and may cover each ofopposite sidewalls in the first direction of a lower portion of the gatestructure 300. The inner spacer 220 may be spaced apart from the gatestructure 300 along the first direction by the channel connectionportion 127, and the inner spacer 220 and the gate structure 300 may notcontact each other.

In an implementation, a cross-section in the first direction of theinner spacer 220 may have a shape of a horseshoe, a crescent shape, or ashape of a semi-circle with a recess on a sidewall thereof. In animplementation, the cross-section in the first direction of the innerspacer 220 may have a shape of a rectangle with a recess on a sidewalland rounded corners of another sidewall.

The inner spacer 220 may include, e.g., a nitride such as siliconnitride, silicon carbonitride, silicon boronitride, or siliconoxynitride.

In an implementation, the semiconductor pattern 126 (e.g., each of thefirst to third semiconductor patterns 126 a, 126 b, and 126 c) may havea first thickness T1 in the third direction, a portion of the gatestructure 300 between the active pattern 105 and the semiconductorpattern 126 or between the semiconductor patterns 126 may have a secondthickness T2 in the third direction, and the inner spacer 220 may have athird thickness T3 in the third direction. The third thickness T3 may besmaller than the second thickness T2. In an implementation, asillustrated in the drawings, the first thickness T1 may be smaller thanthe second and third thicknesses T2 and T3. In an implementation, thefirst thickness T1 may be greater than each of the second and thirdthicknesses T2 and T3, or may be smaller than the second thickness T2but greater than the third thickness T3. The first thickness T1 may beequal to the second thickness T2 or the third thickness T3.

In an implementation, sidewalls of the first to third semiconductorpatterns 126 a, 126 b, and 126 c in the first direction, sidewalls ofthe channel connection portions 127 connected to upper and/or lowerportions of the first to third semiconductor patterns 126 a, 126 b, and126 c in the first direction, and outer sidewalls of the inner spacers220 between the first to third semiconductor patterns 126 a, 126 b, and126 c in the first direction altogether may form an uneven surface.

The source/drain layer 230 may extend (e.g., upwardly) in the thirddirection on the active pattern 105, and may commonly contact thesidewalls of the semiconductor patterns 126 at a plurality of levels,respectively, in the first direction to be connected thereto.

In an implementation, the source/drain layer 230 may contact thesemiconductor patterns 126 and the inner spacers 220 therebetween. Asidewall of the source/drain layer 230 may have an uneven surface,corresponding to the uneven surface of the sidewalls of the first tothird semiconductor patterns 126 a, 126 b, and 126 c, the channelconnection portion 127, and the inner spacers 220.

In an implementation, a portion of the sidewall of the source/drainlayer 230 contacting each of the first to third semiconductor patterns126 a, 126 b, and 126 c may have a concave shape in the first direction,and a portion of the sidewall thereof contacting each of the innerspacers 220 may have a convex shape in the first direction.

In an implementation, the source/drain layer 230 may include singlecrystalline silicon carbide doped with n-type impurities or singlecrystalline silicon doped with n-type impurities, and thus may serve asa source/drain of an NMOS transistor. In an implementation, thesource/drain layer 230 may include single crystalline silicon-germaniumdoped with p-type impurities, and thus may serve as a source/drain of aPMOS transistor.

In an implementation, the source/drain layer 230 may include the n-typeor p-type impurities, and the gate structure 300, the source/drain layer230, and each of the semiconductor patterns 126 serving as a channel mayform the NMOS transistor or the PMOS transistor. The semiconductorpatterns 126 may be formed at a plurality of levels, respectively, alongthe third direction, and thus the semiconductor device may be an MBCFET.

The insulation layer 240 may surround a sidewall of the gate spacer 185and may cover the source/drain layer 230. The insulation layer 240 mayinclude, e.g., an oxide such as silicon oxide.

The semiconductor device may further include a contact plug, a wiring,or the like, which may be electrically connected to the source/drainlayer 230 and/or the gate structure 300.

As described above, the inner spacer 220 may have the third thickness T3smaller than the second thickness T2, which is the thickness of theportion of the gate structure 300 between the semiconductor patterns 126or between the active pattern 105 and the lowermost semiconductorpattern 126.

A space between the semiconductor patterns 126 may be partially filledwith the channel connection portion 127 before forming a second spacerlayer 210 illustrated with reference to FIG. 19 subsequently, and thusthe second spacer layer 210 may entirely fill the space even if thesecond spacer layer 210 is formed with a relatively small amount. Thesecond spacer layer 210 may be formed with the relatively small amount,and thus may be easily removed so that no residue remains on the uppersurface of the active pattern 105 when the second spacer layer 210 isremoved, and the source/drain layer 230 may be effectively formed on theupper surface of the active pattern 105. Accordingly, electricalcharacteristics of the semiconductor device may be improved.

FIGS. 5 to 24 are plan views and cross-sectional views of stages in amethod of manufacturing a semiconductor device in accordance withexample embodiments. Specifically, FIGS. 5, 7, 9, 12 and 22 are the planviews, and FIGS. 6, 8, 10-11, 13-21 and 23-24 are the cross-sectionalviews.

FIGS. 6, 8 and 10 are cross-sectional views taken along lines A-A′ ofcorresponding plan views, respectively, FIGS. 11, 13, 15, 17, 19-20 and23 are cross-sectional views taken along lines B-B′ of correspondingplan views, respectively, and FIGS. 14, 16, 18, and 21 are enlargedcross-sectional views of regions X of corresponding cross-sectionalviews, respectively.

Referring to FIGS. 5 and 6 , a sacrificial layer 110 and a semiconductorlayer 120 may be alternately and repeatedly stacked on a substrate 100.

In an implementation, as illustrated in FIG. 6 , the sacrificial layers110 and the semiconductor layers 120 may be formed at three levels,respectively, on the substrate 100.

In an implementation, the sacrificial layer 110 may include a materialhaving an etch selectivity with respect to the substrate 100 and thesemiconductor layer 120, e.g., silicon-germanium.

In an implementation, the sacrificial layer 110 may be formed byperforming an epitaxial growth process using, e.g., a silicon source gassuch as dichlorosilane (SiH₂Cl₂) gas and a germanium source gas such asgermane (GeH₄) gas, and thus a single crystalline silicon-germanium(SiGe) layer may be formed. In an implementation, the semiconductorlayer 120 may be formed by performing an epitaxial growth process using,e.g., a silicon source gas such as disilane (Si₂H₆) gas, and thus asingle crystalline silicon layer may be formed.

Referring to FIGS. 7 and 8 , an etch mask extending in the firstdirection may be formed on an uppermost one of the semiconductor layers120 (e.g., distal to the substrate 100 in the third direction), and thesemiconductor layer 120, the sacrificial layer 110, and an upper portionof the substrate 100 may be etched using the etch mask.

Accordingly, an active pattern 105 extending in a first direction may beformed on the substrate 100, and a fin structure including sacrificiallines 112 and semiconductor lines 122 alternately and repeatedly stackedon the active pattern 105 may be formed. In an implementation, aplurality of fin structures may be formed on the substrate 100 to bespaced apart from each other in the second direction.

An isolation pattern 130 covering a sidewall of the active pattern 105may be formed on the substrate 100.

Referring to FIGS. 9 to 11 , a dummy gate structure 175 may be formed onthe substrate 100 to partially cover the fin structure and the isolationpattern 130.

In an implementation, a dummy gate insulating layer, a dummy gateelectrode layer, and a dummy gate mask layer may be sequentially formedon the substrate 100 on which the fin structure and the isolationpattern 130 are formed. An etch mask extending in the second directionmay be formed on the dummy gate mask layer, and the dummy gate masklayer may be etched using the etch mask to form a dummy gate mask 165 onthe substrate 100.

The dummy gate insulating layer may include, for example, an oxide suchas silicon oxide. The dummy gate electrode layer may include, forexample, polysilicon. The dummy gate mask layer may include, forexample, a nitride such as silicon nitride.

The dummy gate electrode layer and the dummy gate insulating layer maybe etched using the dummy gate mask 165 as an etch mask to form a dummygate electrode 155 and a dummy gate insulating pattern 145,respectively, on the substrate 100.

The dummy gate structure 175 may include the dummy gate insulatingpattern 145, the dummy gate electrode 155, and the dummy gate mask 165sequentially stacked on the active pattern 105 and a portion of theisolation pattern 130 adjacent thereto. In an implementation, the dummygate structure 175 may extend in the second direction on the finstructure and the isolation pattern 130, and may cover an upper surfaceand opposite sidewalls in the second direction of the fin structure.

Referring to FIGS. 12 to 14 , a gate spacer 185 may be formed on asidewall of the dummy gate structure 175.

In an implementation, after forming a first spacer layer on thesubstrate 100 on which the fin structure, the isolation pattern 130, andthe dummy gate structure 175 are formed, the first spacer layer maybeanisotropically etched to form a gate spacer 185 covering each ofopposite sidewalls of the dummy gate structure 175 in the firstdirection.

An exposed portion of the fin structure may be etched using the dummygate structure 175 and the gate spacer 185 as the etch mask to form afirst opening 190 exposing the active pattern 105 of the substrate 100and a portion of the isolation pattern 130 adjacent thereto in thesecond direction.

In an implementation, the sacrificial lines 112 and the semiconductorlines 122 under the dummy gate structure 175 and the gate spacer 185 maybe patterned into sacrificial patterns 114 and preliminary semiconductorpatterns 124, respectively, and the fin structures extending in thefirst direction may be divided into a plurality of pieces spaced apartfrom each other along the first direction.

Hereinafter, for the convenience of explanation, the dummy gatestructure 175, the gate spacer 185 on each of opposite sidewallsthereof, and the fin structure under the dummy gate structure 175 andthe gate spacer 185 may be referred to as a first structure. In animplementation, the first structure may extend in the second direction,and a plurality of first structures may be spaced apart from each otheralong the first direction.

Referring to FIGS. 15 and 16 , each of opposite sidewalls in the firstdirection of the sacrificial pattern 114 exposed by the first opening190 may be etched to form a first recess 200.

In an implementation, the first recess 200 may be formed by performing awet etching process on the sacrificial pattern 114. In animplementation, the first recess 200 may have a convex shape protrudinginwardly toward a center of the sacrificial pattern 114 along the firstdirection. In an implementation, the first recess 200 may have across-section in the first direction having a shape of a semi-circle.

In an implementation, an end portion (in the first direction) of thepreliminary semiconductor pattern 124 adjacent to the first recess 200may have a shape of a rectangle with rounded corners. A portion of theactive pattern 105 under a lowermost one of the sacrificial patterns 114may have a shape of a trapezoid with rounded corners.

In an implementation, the preliminary semiconductor pattern 124 may havea first thickness T1 (e.g., in the third direction), the sacrificialpattern 114 may have a second thickness T2, and a maximum thickness ofthe first recess 200 may be substantially equal to the second thicknessT2 of the sacrificial pattern 114. In an implementation, the firstthickness T1 may be smaller than the second thickness T2.

Referring to FIGS. 17 and 18 , a first selective epitaxial growth (SEG)process may be performed using surfaces of layers including silicon as aseed, e.g., a surface of the preliminary semiconductor pattern 124, asurface of the sacrificial pattern 114, and an upper surface of theactive pattern 105 exposed by the first opening 190 and the first recess200 as a seed.

In an implementation, a width of the preliminary semiconductor pattern124 in the first direction may be increased, and a thickness of an edgeportion thereof in the third direction may be also increased. Thepreliminary semiconductor patterns 124 having the increased width may besemiconductor patterns 126, respectively.

In an implementation, the semiconductor patterns 126 may include a firstsemiconductor pattern 126 a at an uppermost level (e.g., distal to thesubstrate 100 in the third direction), a third semiconductor pattern 126c at a lowermost level (e.g., proximate to the substrate 100 in thethird direction), and a second semiconductor pattern 126 b therebetween,and the first to third semiconductor patterns 126 a, 126 b, and 126 cmay protrude in the first direction from (e.g., outwardly beyond) thegate spacer 185 in a plan view.

The sacrificial patterns 114 may include silicon-germanium, and thussilicon included in the sacrificial patterns 114 may be also used as theseed in the first SEG process. In an implementation, a channelconnection portion 127 may be formed to cover each of opposite sidewallsof each of the sacrificial patterns 114.

Hereinafter, a portion of the semiconductor pattern 126 increased fromthe preliminary semiconductor pattern 124 in the first direction by thefirst SEG process may be considered as a portion of the semiconductorpattern 126. In an implementation, a portion of the semiconductorpattern 126 increased from the preliminary semiconductor pattern 124 inthe third direction by the first SEG process may be considered as thechannel connection portion 127.

In an implementation, a plurality of channel connection portions 127 maybe formed between neighboring ones of the first to third semiconductorpatterns 126 a, 126 b, and 126 c along the third direction, and mayconnect the first to third semiconductor patterns 126 a, 126 b, and 126c with each other. In an implementation, the channel connection portion127 may be also formed between the third semiconductor pattern 126 c andthe active pattern 105, and may connect the third semiconductor pattern126 c with the active pattern 105. The first to third semiconductorpatterns 126 a, 126 b, and 126 c and the channel connection portions 127therebetween may each include single crystalline silicon.

In an implementation, the channel connection portion 127 may have aconvex shape protruding inwardly toward the center of each sacrificialpattern 114 along the first direction. In an implementation, across-section in the first direction of the channel connection portion127 may have a shape of a C or a reversed C. In an implementation, across-section in the first direction of the channel connection portion127 may have a shape of a ring in which a portion is cut in the firstdirection.

As the first SEG process is performed, the channel connection portion127 may be formed at upper and lower portions of the first recess 200,respectively, and thus a maximum thickness in the third direction of thefirst recess 200 may be decreased, and the first recess 200 may then bea second recess 205.

In an implementation, the semiconductor pattern 126 may have a thicknessafter the first SEG process, which is substantially the same as that ofthe semiconductor pattern 126 before the first SEG process, e.g., thefirst thickness T1, and the sacrificial pattern 114 may also have athickness after the first SEG process, which is substantially the sameas that of the sacrificial pattern 114 before the first SEG process,e.g., the second thickness T2. In an implementation, the second recess205 may have a thickness smaller than that of the sacrificial pattern114, e.g., the third thickness T3. In an implementation, the thirdthickness T3 of the second recess 205 may be a distance between anupward-facing lowermost surface and a downward-facing uppermost surfaceof the channel connection portion 127.

The first SEG process may also be performed on an upper surface of theactive pattern 105 exposed by the first opening 190, and thus athickness of the active pattern 105 may be increased.

Referring to FIGS. 19 to 21 , a second spacer layer 210 may be formed onthe dummy gate structure 175, the gate spacer 185, the fin structure,the active pattern 105, and the isolation pattern 130, and the secondspacer layer 210 may be anisotropically etched to form an inner spacer220 at least partially filling the second recess 205.

The inner spacer 220 may be formed on a sidewall of the sacrificialpattern 114 between neighboring ones of the first to third semiconductorpatterns 126 a, 126 b, and 126 c in the third direction. In animplementation, the inner spacer 220 may be spaced apart from thesacrificial pattern 114 by the channel connection portion 127 so as notto contact the sacrificial pattern 114 (e.g., due to the presence of thechannel connection portion 127).

In an implementation, a plurality of inner spacers 220 may be formed(e.g., spaced apart) along the third direction, and each of the innerspacers 220 may have a maximum thickness substantially equal to that ofthe second recess 205, e.g., the thickness T3.

In an implementation, an inner sidewall of the inner spacer 220contacting the sacrificial pattern 114 may have a convex shapeprotruding inwardly toward the center of the sacrificial pattern 114along the first direction, and an outer sidewall of the inner spacer 220exposed by or to the first opening 190 may have a concave shape that isopen along or toward the first direction. In an implementation, theinner spacer 220 may have a cross-section in the first direction havinga shape of a semi-circle.

In an implementation, sidewalls of the first to third semiconductorpatterns 126 a, 126 b, and 126 c in the first direction, sidewalls ofthe channel connection portions 127 connected to upper and/or lowerportions of the first to third semiconductor patterns 126 a, 126 b, and126 c in the first direction, and the outer sidewalls of the innerspacers 220 between the first to third semiconductor patterns 126 a, 126b, and 126 c in the first direction altogether may form an unevensurface. The sidewalls of the first to third semiconductor patterns 126a, 126 b, and 126 c may protrude in the first direction, and the outersidewalls of the inner spacers 220 may be recessed in the firstdirection.

In an implementation, the outer sidewall of the inner spacer 220 mayprotrude in the first direction from or beyond the sidewall of the gatespacer 185 in a plan view. In an implementation, the sidewall of thegate spacer 185 may protrude in the first direction from or beyond theouter sidewall of the inner spacer 220 in a plan view.

Referring to FIGS. 22 and 23 , a second selective epitaxial growth (SEG)process may be performed using the sidewalls of the semiconductorpatterns 126 and the upper surface of the active pattern 105 exposed bythe first opening 190 as a seed, so that a source/drain layer 230 may beformed on the sidewalls of the semiconductor patterns 126. Thesource/drain layer 230 may fill the first opening 190 on the activepattern 105, and further grow in the third direction to contact a lowersidewall of the gate spacer 185.

During the second SEG process, the channel connection portion 127 andthe inner spacer 220 are sequentially stacked on the sidewall of thesacrificial pattern 114, and thus the sacrificial pattern 114 may not beused as a seed. In an implementation, portions of the channel connectionportion 127 directly on and beneath the semiconductor pattern 126 may beexposed by the first opening 190, and thus may be used as a seed for thesecond SEG process. In an implementation, the sacrificial pattern 114may not contact the source/drain layer 230 due to the presence of thechannel connection portion 127 and the inner spacer 220. In animplementation, the portions of the channel connection portion 127directly on and beneath the semiconductor pattern 126 may at leastpartially contact the source/drain layer 230.

In an implementation, the second SEG process may be performed using asilicon source gas, e.g., disilane (Si₂H₆) gas, and a carbon source gas,e.g., SiH₃CH₃ gas, and thus a single crystalline silicon carbide (SiC)layer may be formed. In an implementation, the second SEG process may beperformed using only a silicon source gas, e.g., disilane (Si₂H₆) gas,and thus a single crystalline silicon layer may be formed. Thesource/drain layer 230 may serve as a source/drain of an NMOStransistor.

In an implementation, the second SEG process may be performed using asilicon source gas, e.g., dichlorosilane (SiH₂Cl₂) gas, and a germaniumsource gas, e.g., germane (GeH₄) gas, and thus a single crystallinesilicon-germanium (SiGe) layer may be formed. The source/drain layer 230may serve as a source/drain of a PMOS transistor.

In an implementation, the source/drain layer 230 may be formed tocontact the semiconductor patterns 126 and the inner spacers 220therebetween. A sidewall of the source/drain layer 230 may also have anuneven surface, corresponding to the uneven surface of the sidewalls ofthe first to third semiconductor patterns 126 a, 126 b, and 126 c, thechannel connection portion 127, and the inner spacers 220.

In an implementation, a portion of the sidewall of the source/drainlayer 230 contacting each of the first to third semiconductor patterns126 a, 126 b, and 126 c may have a concave shape in the first direction,and a portion of the sidewall of the source/drain layer 230 contactingeach of the inner spacers 220 may have a convex shape in the firstdirection.

Referring to FIG. 24 , after forming the insulation layer 240 on thesubstrate 100 to cover the first structure and the source/drain layer230, the insulation layer 240 may be planarized until an upper surfaceof the dummy gate electrode 155 of the first structure is exposed. Thedummy gate mask 165 may be also removed, and an upper portion of thegate spacer 185 may be partially removed.

The planarization process may be performed by a chemical mechanicalpolishing (CMP) process and/or an etch back process.

The exposed dummy gate electrode 155, the dummy gate insulating pattern145 thereunder, and the sacrificial patterns 114 may be removed, e.g.,by a wet etching process and/or a dry etching process, and a secondopening 250 may be formed to expose an inner sidewall of the gate spacer185, an inner sidewall of the channel connection portion 127, a surfaceof the semiconductor pattern 126, and the upper surface of the activepattern 105.

Referring to FIGS. 1 to 4 again, a gate structure 300 may be formed onthe substrate 100 to fill the second opening 250.

In an implementation, an interface pattern 260 may be formed byperforming a thermal oxidation process on the upper surface of theactive pattern 105, the inner sidewall of the channel connection portion127, and the surface of the semiconductor pattern 126 exposed by thesecond opening 250. A gate insulating layer and a work function controllayer may be conformally formed on a surface of the interface pattern260, and a gate electrode layer may be formed to sufficiently fill aremaining portion of the second opening 250.

The gate insulating layer, the work function control layer, and the gateelectrode layer may be formed by a chemical vapor deposition (CVD)process, an atomic layer deposition (ALD) process, or a physical vapordeposition (PVD) process. In an implementation, the interface pattern260 may be also formed by the CVD process or the ALD process instead ofthe thermal oxidation process.

The gate electrode layer, the work function control layer, and the gateinsulating layer may be planarized until an upper surface of theinsulation layer 240 is exposed, so that a gate electrode 290, a workfunction control pattern 280, and a gate insulating pattern 270 may berespectively formed. The interface pattern 260, the gate insulatingpattern 270, the work function control pattern 280, and the gateelectrode 290 may form the gate structure 300.

The interface pattern 260 may include, e.g., an oxide such as siliconoxide. The gate insulating pattern 270 may include, e.g., a metal oxidehaving a high permittivity such as hafnium oxide, tantalum oxide,zirconium oxide, or the like. The work function control pattern 280 mayinclude, e.g., titanium nitride, tantalum nitride, tungsten nitride,aluminum oxide, or the like. The gate electrode 290 may include, e.g., ametal such as titanium and aluminum, a metal alloy, or a nitride orcarbide of the metal.

The interface pattern 260 may be formed on upper and lower surfaces ofthe semiconductor pattern 126 and the inner sidewall of the channelconnection portion 127 exposed by the second opening 250 and includingsingle crystalline silicon, and may entirely surround an edge of thesecond opening 250. The active pattern 105 may also include singlecrystal silicon, and thus the interface pattern 260 may be also formedon the upper surface of the active pattern 105.

In an implementation, a sidewall of the interface pattern 260 of thegate structure 300 facing the source/drain layer 230 may have a concaveshape that is in the first direction toward the source/drain layer 230,and may contact the inner sidewall of the channel connection portion 127connecting the semiconductor patterns 126.

In an implementation, the gate structure 300 and the inner spacer 220may be spaced apart from each other by the channel connection portion127, so as not to be in contact with each other.

In an implementation, the gate structure 300 may have a thicknesssubstantially equal to the thickness of the sacrificial pattern 114,e.g., the gate structure 300 may have the second thickness T2. The innerspacer 220 may have a thickness smaller than the second thickness T2 ofthe sacrificial pattern 114, e.g., the inner spacer 220 may have thethird thickness T3.

As described above, the first SEG process may be performed on thesurfaces of the semiconductor patterns 126 exposed by the first opening190 and the first recess 200 to form the second recess 205 having athickness smaller than that of the first recess 200. Thus, the secondspacer layer 210 for forming the inner spacer 220 may be formed toentirely fill the second recess 205 even if the second spacer layer isformed with a relatively small amount. Additionally, the second spacerlayer 210 may be more easily removed after the inner spacer 220 isformed, and a residue may not remain on the upper surface of the activepattern 105. Accordingly, the upper surface of the active pattern 105may be entirely exposed by the first opening 190, and the source/drainlayer 230 may be effectively formed on the upper surface of the exposedactive pattern 105, and electrical characteristics of the semiconductordevice may be improved.

The sacrificial pattern 114 may include silicon-germanium, and the firstSEG process may be performed using surfaces of layers including siliconas a seed, and thus the channel connection portion 127 connecting theactive pattern 105 and the first to third semiconductor patterns 126 a,126 b, and 126 c with each other in the third direction may be formed onthe sidewall of the sacrificial pattern 114. The channel connectionportion 127 may include single crystalline silicon, and the interfacepattern 260 may be also formed on the inner sidewall of the channelconnection portion 127 exposed by the second opening 250, and the gateinsulating pattern 270, the work function control pattern 280, and thegate electrode 290 sequentially stacked may be spaced apart to beelectrically insulated from the source/drain layer 230 by the interfacepattern 260, the channel connection portion 127 and the inner spacer220.

FIGS. 25 to 27 are cross-sectional views of stages in a method ofmanufacturing a semiconductor device in accordance with exampleembodiments, and are cross-sectional views taken along lines B-B′ ofcorresponding plan views, respectively. This manufacturing method mayinclude processes substantially the same as or similar to thoseillustrated with reference to FIGS. 5 to 24 and 1 to 4 except for shapesof some components, and thus like reference numerals refer to likeelements, and repeated descriptions thereon may be omitted herein.

Referring to FIGS. 25 and 26 , processes substantially the same as orsimilar to those illustrated with reference to FIGS. 5 to 24 may beperformed.

In an implementation, when the sacrificial patterns 114 are removed by,e.g., a wet etching process and/or a dry etching process, surfaces ofthe semiconductor patterns 126 on and beneath the sacrificial patterns114 may be also partially removed.

In an implementation, the wet etching process and/or the dry etchingprocess for removing the sacrificial patterns 114 may be performed byusing an etching solution and/or etching gas for selectively removingsilicon-germanium. In an implementation, the surfaces of thesemiconductor patterns 126 including single crystalline silicon and theupper surfaces of the active patterns 105 may be also partially removedalong with the sacrificial patterns 114.

In an implementation, a portion of the second opening 250 between theactive pattern 105 and the third semiconductor pattern 126 c, and aportion of the second opening 250 between the first to thirdsemiconductor patterns 126 a, 126 b, and 126 c may be enlarged in thethird direction.

In an implementation, after the wet etching process and/or the dryetching process is performed, a central portion in the first directionof the first semiconductor pattern 126 a at an uppermost level among thesemiconductor patterns 126 may have a fourth thickness T4 smaller thanthe first thickness T1, and a central portion in the first direction ofeach of the second and third semiconductor patterns 126 b and 126 cthereunder may have a fifth thickness T5 smaller than the fourththickness T4, The inner spacer 220 may have the third thickness T3,which is the same as that before the wet etching process and/or the dryetching process.

Referring to FIG. 27 , processes substantially the same as or similar tothose described with reference to FIGS. 1 to 4 may be performed to fromthe gate structure 300 filling the second opening 250.

In an implementation, the gate structure 300 may have a sixth thicknessT6 which is greater than the third thickness T3 of the inner spacer 220,the fourth thickness T4 of the central portion of the firstsemiconductor pattern 126 a, and the fifth thickness T5 of the centralportion of each of the second and third semiconductor patterns 126 b and126 c.

FIGS. 28 and 29 are cross-sectional views illustrating semiconductordevices in accordance with example embodiments, and are enlargedcross-sectional views of regions X of the cross-sectional view takenalong the line B-B′ of FIG. 1 . The semiconductor devices aresubstantially the same or similar to the semiconductor devicesillustrated with reference to FIGS. 1 to 4 except for shapes ofsemiconductor patterns, and like reference numerals refer to likeelements, and repeated descriptions thereon may be omitted herein.

Referring to FIG. 28 , a portion of the channel connection portion 127contacting the source/drain layer 230 may have thickness in the thirddirection greater than that of other portions of the channel connectionportion 127.

In an implementation, the first SEG process may be performed more on aportion of the preliminary semiconductor pattern 124 exposed by thefirst opening 190 than on a portion of the preliminary semiconductorpattern 124 exposed by the first recess 200, so that the portion of thesemiconductor pattern 126 contacting the source/drain layer 230 may havethe relatively large thickness.

In an implementation, a cross-section in the first direction of thechannel connection portion 127 may have a shape of a C or reversed C inwhich ends of the C have a relatively larger thickness.

In an implementation, an outer sidewall of the inner spacer 220contacting the source/drain layer 230 may have a seventh thickness T7(e.g., in the third direction) smaller than the third thickness T3,which is a maximum thickness of the inner spacer 220.

Referring to FIG. 29 , a portion of the channel connection portion 127contacting the source/drain layer 230 may have thickness in the thirddirection smaller than that of other portions of the channel connectionportion 127.

In an implementation, the first SEG process may be performed more on aportion of the preliminary semiconductor pattern 124 exposed by thefirst recess 200 than on a portion of the preliminary semiconductorpattern 124 exposed by the first opening 190, so that the portion of thesemiconductor pattern 126 contacting the source/drain layer 230 may havethe relatively small thickness.

In an implementation, a cross-section in the first direction of thechannel connection portion 127 may have a shape of a C or reversed C inwhich ends of the C have a relatively smaller thickness.

In an implementation, the outer sidewall of the inner spacer 220contacting the source/drain layer 230 may have a thickness substantiallyequal to the second thickness T2 of the portion of the gate structure300 between the semiconductor patterns 126. In an implementation, aportion of the channel connection portion 127 contacting thesemiconductor pattern 126 may have a thickness in the third directionthat may increase as it becomes more distant from the source/drain layer230 (e.g., moving inwardly in the first direction).

FIGS. 30 and 31 are cross-sectional views illustrating semiconductordevices in accordance with example embodiments, and are cross-sectionalviews taken along the line B-B′ of FIG. 1 . This semiconductor devicesmay be substantially the same as or similar to the semiconductor devicesillustrated with reference to FIGS. 1 to 4 except that a metal silicidepattern and a contact plug are further formed on the source/drain layer,and thus like reference numerals refer to like elements, and repeateddescriptions thereon may be omitted herein.

Referring to FIG. 30 , a second insulating interlayer 310 may be formedon the gate structure 300 and the insulation layer 240, a contact holemay be formed through the insulation layer 240 and the second insulatinginterlayer 310 to expose an upper surface of the source/drain layer 230,and a contact plug 330 may be formed to fill the contact hole.

In an implementation, a plurality of contact plugs 330 may be formedalong a first direction.

A metal silicide pattern 320 may be further formed on the source/drainlayer 230. In an implementation, after forming a metal layer on theupper surface of the source/drain layer 230 exposed by the contact hole,a sidewall of the insulation layer 240, and a sidewall and an uppersurface of the second insulating interlayer 310, a heat treatmentprocess may be performed on the metal layer to form the metal silicidepattern 320 on the source/drain layer 230.

In an implementation, the metal silicide pattern 320 may include, e.g.,nickel silicide, cobalt silicide, titanium silicide, or the like, andthe contact plug 330 may include, e.g., a metal, a metal nitride, and/orpolysilicon doped with impurities.

In an implementation, the contact plug 330 may have a structure in whicha conductive pattern and a barrier pattern covering a sidewall thereofare stacked. The conductive pattern may include, e.g., a metal such ascopper, tungsten, or aluminum. The barrier pattern may include, e.g., ametal such as titanium or tantalum, or a metal nitride such as titaniumnitride or tantalum nitride.

In an implementation, as illustrated in FIG. 30 , a lower (e.g.,substrate 100-facing) surface of the contact plug 330 may be at the sameheight as the upper surface of the source/drain layer 230. In animplementation, the contact plug 330 may be formed to extend to havevarious depths in the third direction, so that the lower surface of thecontact plug 330 may be formed to be lower than the upper surface of thesource/drain layer 230.

Referring to FIG. 31 , the lower surface of the contact plug 330 may belower than a lower surface of the first semiconductor pattern 126 a andhigher than an upper surface of the third semiconductor pattern 126 c,and, for example, may be formed at a height between lower and uppersurfaces of the second semiconductor pattern 126 b.

In an implementation, the lower surface of the contact plug 330 may beformed at a height between the lower surface of the first semiconductorpattern 126 a and the upper surface of the second semiconductor pattern126 b, or between the lower surface of the second semiconductor pattern126 b and the upper surface of the third semiconductor pattern 126 c.

In an implementation, as illustrated in FIG. 31 , the metal silicidepattern 320 on the source/drain layer 230 may have a cylindrical shape.In an implementation, the metal silicide pattern 320 may have a pillarshape.

By way of summation and review, an inner spacer layer for forming theinner spacer may be formed to completely fill the space between the gatestructure and the source/drain layer between neighboring ones of theplurality of channels. If the inner spacer layer has a thick thicknessin order to completely fill the space, a residue may remain whenremoving the inner spacer layer.

One or more embodiments may provide a semiconductor device having aplurality of channels vertically stacked.

Example embodiments provide a semiconductor device having improvedelectrical characteristics.

In a method of manufacturing a semiconductor device according to exampleembodiments, a selective epitaxial growth (SEG) process may be furtherperformed on surfaces of the channels in order to decrease a thicknessof a recess in which an inner spacer is formed between the channels.Accordingly, even if an inner spacer layer for forming the inner spaceris provided in a relatively small amount on an active pattern, the innerspacer layer may be formed to completely fill the recess between thechannels, and a residue may be completely removed so as not to remainwhen the inner spacer layer is removed.

Example embodiments have been disclosed herein, and although specificterms are employed, they are used and are to be interpreted in a genericand descriptive sense only and not for purpose of limitation. In someinstances, as would be apparent to one of ordinary skill in the art asof the filing of the present application, features, characteristics,and/or elements described in connection with a particular embodiment maybe used singly or in combination with features, characteristics, and/orelements described in connection with other embodiments unless otherwisespecifically indicated. Accordingly, it will be understood by those ofskill in the art that various changes in form and details may be madewithout departing from the spirit and scope of the present invention asset forth in the following claims.

What is claimed is:
 1. A method of manufacturing a semiconductor device,the method comprising: forming sacrificial lines and semiconductor lineson a substrate, each of the sacrificial lines and the semiconductorlines extending in a first direction substantially parallel to an uppersurface of the substrate, and the sacrificial lines and thesemiconductor lines alternately and repeatedly stacked on the substrate;etching the sacrificial lines and the semiconductor lines to formsacrificial patterns and preliminary semiconductor patterns,respectively; partially etching opposite lateral portions in the firstdirection of each of the sacrificial patterns to form first recesses,respectively; performing a first selective epitaxial growth (SEG)process using surfaces of the preliminary semiconductor patterns andsidewalls of the sacrificial patterns exposed by the first recesses as aseed such that a width in the first direction of each of the preliminarysemiconductor patterns is increased to form semiconductor patterns andthat a channel connection portion is formed to connect the semiconductorpatterns; forming inner spacers in the first recesses, respectively;forming source/drain layers to contact opposite sidewalls in the firstdirection of the semiconductor patterns, respectively; and replacing thesacrificial patterns with a gate structure.
 2. The method as claimed inclaim 1, wherein the sacrificial lines and the semiconductor linesinclude silicon and silicon-germanium, respectively, and the channelconnection portion includes silicon.
 3. The method as claimed in claim1, wherein the channel connection portion contacts a lower surface ofone of the semiconductor patterns overlying the channel connectionportion and an upper surface of one of the semiconductor patternsunderlying the channel connection portion.
 4. The method as claimed inclaim 1, wherein: an active pattern is formed on the substrate, theactive pattern extending in the first direction and contacts a lowermostone of the sacrificial lines, and an upper portion of the active patternis etched to form a second recess during etching the sacrificial linesand the semiconductor lines.
 5. The method as claimed in claim 4,wherein the first SEG process is performed using a surface of the activepattern exposed by the second recess as a seed.
 6. The method as claimedin claim 4, further comprising, prior to etching the sacrificial linesand the semiconductor lines: forming a dummy gate structure on theactive pattern, the dummy gate structure extending in a second directionsubstantially parallel to the upper surface of the substrate andcrossing the first direction; and forming gate spacers on oppositesidewalls in the first direction of the dummy gate structure,respectively, wherein etching the sacrificial lines and thesemiconductor lines is performed using the dummy gate structure and thegate spacers as an etching mask.
 7. The method as claimed in claim 6,wherein forming the inner spacers includes: forming a spacer layer onthe substrate to cover the active pattern, the semiconductor patterns,the sacrificial patterns, the dummy gate structure, and the gatespacers; and anisotropically etching the spacer layer.
 8. The method asclaimed in claim 7, wherein anisotropically etching the spacer layerincludes removing a portion of the spacer layer on an upper surface ofthe active pattern.
 9. The method as claimed in claim 6, whereinreplacing the sacrificial patterns with the gate structure includes:forming an insulating interlayer on the substrate to cover the dummygate structure; planarizing the insulating interlayer until an uppersurface of the dummy gate structure is exposed; removing the exposeddummy gate structure and the sacrificial patterns under the dummy gatestructure to form a gap exposing inner sidewalls of the gate spacers,surfaces of the semiconductor patterns and a surface of the activepattern; and forming the gate structure in the gap.
 10. The method asclaimed in claim 9, wherein forming the gate structure includes: formingan interface pattern by oxidizing exposed surfaces of the semiconductorpatterns and the surface of the active pattern; and forming a gateinsulation pattern, a work function control pattern and a gate electrodesequentially stacked in the gap.
 11. The method as claimed in claim 4,wherein forming the source/drain layer includes performing a second SEGusing a surface of the active pattern and sidewalls of the semiconductorpatterns as a seed.
 12. A method of manufacturing a semiconductordevice, the method comprising: forming an active pattern on a substrate,the active pattern extending in a first direction substantially parallelto an upper surface of the substrate; forming sacrificial lines andsemiconductor lines on the active pattern, each of the sacrificial linesand the semiconductor lines extending in the first direction, and thesacrificial lines and the semiconductor lines alternately and repeatedlystacked; etching the sacrificial lines and the semiconductor lines toform sacrificial patterns and preliminary semiconductor patterns,respectively, an upper portion of the active pattern being etched toform a first recess; partially etching opposite lateral portions in thefirst direction of each of the sacrificial patterns to form secondrecesses, respectively; performing a first SEG process using surfaces ofthe preliminary semiconductor patterns and sidewalls of the sacrificialpatterns exposed by the second recesses and a surface of the activepattern exposed by the first recess as a seed such that a width in thefirst direction of each of the preliminary semiconductor patterns isincreased to form semiconductor patterns and that a channel connectionportion is formed to connect the semiconductor patterns with each otherand a lowermost one of the semiconductor patterns and the active patternwith each other; forming inner spacers in the second recesses,respectively; forming source/drain layers to contact opposite sidewallsin the first direction of the semiconductor patterns, respectively; andreplacing the sacrificial patterns with a gate structure.
 13. The methodas claimed in claim 12, wherein the sacrificial lines and thesemiconductor lines include silicon and silicon-germanium, respectively,and the channel connection portion includes silicon.
 14. The method asclaimed in claim 12, wherein the channel connection portion contacts alower surface of one of the semiconductor patterns overlying the channelconnection portion and an upper surface of one of the semiconductorpatterns underlying the channel connection portion.
 15. The method asclaimed in claim 12, further comprising, prior to etching thesacrificial lines and the semiconductor lines: forming a dummy gatestructure on the active pattern, the dummy gate structure extending in asecond direction substantially parallel to the upper surface of thesubstrate and crossing the first direction; and forming gate spacers onopposite sidewalls in the first direction of the dummy gate structure,respectively, wherein etching the sacrificial lines and thesemiconductor lines is performed using the dummy gate structure and thegate spacers as an etching mask.
 16. The method as claimed in claim 15,wherein forming the inner spacers includes: forming a spacer layer onthe substrate to cover the active pattern, the semiconductor patterns,the sacrificial patterns, the dummy gate structure and the gate spacers;and anisotropically etching the spacer layer.
 17. The method as claimedin claim 16, wherein anisotropically etching the spacer layer includesremoving a portion of the spacer layer on an upper surface of the activepattern.
 18. The method as claimed in claim 15, wherein replacing thesacrificial patterns with the gate structure includes: forming aninsulating interlayer on the substrate to cover the dummy gatestructure; planarizing the insulating interlayer until an upper surfaceof the dummy gate structure is exposed; removing the exposed dummy gatestructure and the sacrificial patterns under the dummy gate structure toform a gap exposing inner sidewalls of the gate spacers, surfaces of thesemiconductor patterns and a surface of the active pattern; and formingthe gate structure in the gap.
 19. The method as claimed in claim 12,wherein forming the source/drain layer includes performing a second SEGusing a surface of the active pattern and sidewalls of the semiconductorpatterns as a seed.
 20. A method of manufacturing a semiconductordevice, the method comprising: alternately and repeatedly stackingsacrificial layers and semiconductor layers on a substrate; partiallyetching the semiconductor layers, the sacrificial layers, and an upperportion of the substrate to form semiconductor lines, sacrificial lines,and an active pattern, respectively, each of the semiconductor lines,the sacrificial lines, and the active pattern extending in a firstdirection substantially parallel to an upper surface of the substrate;forming a dummy gate structure on the active pattern, the dummy gatestructure extending in a second direction substantially parallel to theupper surface of the substrate and crossing the first direction; forminggate spacers on opposite sidewalls in the first direction of the dummygate structure, respectively; etching the sacrificial lines, thesemiconductor lines, and an upper portion of the active pattern to formsacrificial patterns, preliminary semiconductor patterns, and a firstrecess, respectively; partially etching opposite lateral portions in thefirst direction of each of the sacrificial patterns to form secondrecesses, respectively; performing a first SEG process using surfaces ofthe preliminary semiconductor patterns and sidewalls of the sacrificialpatterns exposed by the second recesses and a surface of the activepattern exposed by the first recess as a seed such that a width in thefirst direction of each of the preliminary semiconductor patterns isincreased to form semiconductor patterns and that a channel connectionportion is formed to connect the semiconductor patterns with each otherand a lowermost one of the semiconductor patterns and the active patternwith each other; forming inner spacers in the second recesses,respectively; performing a second SEG using a surface of the activepattern and sidewalls in the first direction of the semiconductorpatterns as a seed to form source/drain layers to contact oppositesidewalls in the first direction of the semiconductor patterns,respectively; and replacing the sacrificial patterns and the dummy gatestructure with a gate structure.